A 70-yrs-old female patient was readmitted to a local hospital with fever and chills following cardiac surgery at a major teaching institution. Blood cultures were taken and a gram-positive coccus grew-positive coccus grew from the blood cultures within 24-hours, Initial tests indicated that this isolate was resistant to penicillin. Which of the following is the most likely identification?

Enterococcus Enterococci cause a wide variety of infections ranging from less serious--for example, urinary tract infections--to very serious, such as septicemia. A gram-positive coccus resistant to penicillin must be assumed to be entero coccus until other, more definitive biochemical testing places the isolate in one of the more esoteric groups of gram-positive cocci. Once isolated, there are a variety of tests to speciate enterococci. However, penicillinresistant, non_ vancomycin-resistant, gram-positive cocci are most likely E. faecium. There are a variety of mechanisms for vancomycin resistance in E. faecium and they have been termed Van A, B, or C. These isolates have become one of the most feared nosocomial pathogens in the hospital environment. Unfounately, no approved antibiotics can success fully treat vancomycin-resistant enterococci (VRE)--only some experimental antibiotics such as Synercid.